A data calibration system based on a power collection terminal

Abstract

The application relates to the technical field of electric data testing, in particular to a data calibration system based on a power collection terminal, which comprises the following steps: collecting partial discharge signals; connecting to a grounding network of an open-type transformer substation, injecting preset characteristic calibration signals at spatial distribution nodes of the grounding network; controlling the calibration signals, establishing a distributed calibration benchmark by comparing the measurement results of different terminals on signals from different calibration nodes, and establishing a gradient calibration parameter distribution strategy according to the distance relationship between the power collection terminal and each calibration node and the grounding impedance relationship; based on the detection data of at least two power collection terminals on the same partial discharge source, calculating the spatial position of the discharge source through a signal arrival time difference and signal attenuation characteristics, and obtaining the measurement accuracy of each power collection terminal; monitoring the long-term evolution trend of the partial discharge signals, identifying the insulation aging state of equipment, and dynamically adjusting the calibration parameters of the corresponding power collection terminal according to the aging state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric data testing, in particular to a data calibration system based on a power collection terminal. BACKGROUND

[0002] With the continuous advancement of smart grid construction, power collection terminals, as the core equipment of power system data collection, are widely used in key links such as electric energy measurement, power quality monitoring and load control at substations, distribution networks and user sides. The power collection terminal collects various electrical parameters of the power system in real time through the built-in current and voltage sensors, and transmits the collected data to the upper monitoring system, providing data support for the safe and stable operation of the power grid and accurate measurement.

[0003] However, in actual operation, the measurement accuracy of the power collection terminal will be affected by various factors and produce deviations. The main error sources include: sensor zero drift and sensitivity change caused by temperature change, device aging caused by long-term operation, signal distortion caused by electromagnetic interference, and time synchronization error caused by system clock deviation. These errors will accumulate and affect the measurement accuracy of the power collection terminal, and further affect the fairness of electric energy measurement and the reliability of power grid operation state evaluation.

[0004] Currently, the calibration of power collection terminals mainly relies on periodic offline verification method, that is, the equipment is disassembled and sent to professional verification institutions for detection and adjustment. This method has the defects of long verification period, high cost and inability to reflect the state change of the equipment in real time. Although some high-end devices use hardware temperature compensation circuit or simple software correction algorithm, these methods can only compensate for a single error source and cannot cope with the comprehensive error caused by the coupling of multiple factors under complex working conditions, and lack of adaptive ability.

[0005] Therefore, a data calibration system based on a power collection terminal is proposed. SUMMARY

[0006] The application aims to provide a data calibration system based on power collection terminals, comprising collecting partial discharge signals; connecting to the grounding network of an open substation, injecting calibration signals with preset characteristics at the spatial distribution nodes of the grounding network; controlling the calibration signals, establishing a distributed calibration reference by comparing the measurement results of different terminals on signals from different calibration nodes, and establishing a gradient calibration parameter distribution strategy according to the distance and grounding impedance relationship between the power collection terminals and each calibration node; based on the detection data of at least two power collection terminals on the same partial discharge source, calculating the spatial position of the discharge source through the signal arrival time difference and signal attenuation characteristics, and obtaining the measurement accuracy of each power collection terminal; monitoring the long-term evolution trend of the partial discharge signals, identifying the insulation aging state of the equipment, and dynamically adjusting the calibration parameters of the corresponding power collection terminal according to the aging state.

[0007] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0008] A data calibration system based on power collection terminals, comprising:

[0009] A power collection terminal for collecting partial discharge signals;

[0010] A calibration signal generation module connected to the grounding network of an open substation for injecting calibration signals with preset characteristics at the spatial distribution nodes of the grounding network;

[0011] A data processing center, comprising:

[0012] A calibration reference establishment unit for controlling the calibration signals and receiving the detection data of each power collection terminal on the calibration signals, establishing a distributed calibration reference by comparing the measurement results of different terminals on signals from different calibration nodes, and establishing a gradient calibration parameter distribution strategy according to the distance and grounding impedance relationship between the power collection terminals and each calibration node;

[0013] A spatial positioning verification unit for calculating the spatial position of the discharge source through the signal arrival time difference and signal attenuation characteristics based on the detection data of at least two power collection terminals on the same partial discharge source, and matching and verifying with the pre-stored equipment spatial coordinate database to obtain the measurement accuracy of each power collection terminal;

[0014] A dynamic parameter adjustment unit for monitoring the long-term evolution trend of the partial discharge signals, identifying the insulation aging state of the equipment, and dynamically adjusting the calibration parameters of the corresponding power collection terminal according to the aging state.

[0015] Preferably, the spatial distribution nodes include a main calibration node arranged at the geometric center of the main grounding grid of the substation, sub-area calibration nodes arranged at the grounding collection points of different voltage level areas respectively, and boundary calibration nodes arranged at the key positions of the boundary of the grounding network, the distance between each node is determined according to the attenuation characteristics of the calibration signal in the grounding network, forming a distributed calibration reference network and a calibration redundancy mechanism.

[0016] The calibration signal generation module includes a multi-channel synchronous signal generator for simultaneously generating calibration signals with different identification characteristics to the main calibration node, the sub-area calibration nodes and the boundary calibration nodes; an impedance matching network connected between each calibration node and the grounding network for adjusting the injection parameters of the calibration signal according to the grounding impedance characteristics of different injection points; and a node state monitoring module for monitoring the working state and signal injection of each calibration node in real time and switching to a backup calibration path when a node fault is detected.

[0017] Preferably, the acquisition method of the distributed calibration reference includes recording the signal amplitude, phase and harmonic distortion data of each power collection terminal during the injection of the calibration signal, and establishing a response characteristic data set; taking the power collection terminal with the most stable and highest measurement accuracy in the response characteristic data set as the reference terminal, calculating the calibration coefficients of the power collection terminal relative to the reference terminal, including amplitude calibration coefficient and phase calibration coefficient; verifying the effectiveness of the calibration coefficients by injecting a verification signal with known amplitude and phase, and establishing a confidence interval for the calibration coefficients.

[0018] Preferably, the acquisition method of the gradient calibration parameter distribution strategy includes establishing an electrical network containing conductor material, cross-sectional area and connection relationship based on the measured data of the grounding network of the substation.

[0019] The simulation results of the low-frequency calibration signal in the electrical network are calculated, including transmission attenuation and phase delay characteristics; the weight factors of each power collection terminal affected by different calibration nodes are calculated according to the simulation results, and the weight factor distribution is obtained.

[0020] According to the weight factor distribution, the power collection terminals are divided into a main calibration area, a secondary calibration area and a boundary calibration area, and different first calibration parameters and calibration frequencies are assigned.

[0021] Preferably, the spatial position of the discharge source is specifically obtained by: each power collection terminal recording the signal peak amplitude and energy integral value of the same partial discharge event, and calculating the signal strength ratio matrix between the terminals; based on the physical principle that the signal strength is inversely proportional to the square of the distance when the electromagnetic wave propagates in the air, the relative distance ratio of each power collection terminal to the discharge source is calculated by using the signal strength ratio matrix; the device region where the partial discharge occurs is determined according to the pre-stored device spatial coordinate database, and the spatial constraint boundary of the discharge source position is established; and the spatial position matching the relative distance ratio of each power collection terminal is searched within the constraint boundary as the spatial position of the discharge source.

[0022] Preferably, the specific process of obtaining the measurement accuracy of each power collection terminal includes: collecting the measurement data of multiple power collection terminals monitoring the same device within the same time window to obtain the multi-terminal consistency, including the standard deviation and the coefficient of variation of the measurement results;

[0023] The measurement data of each power collection terminal is associated with the periodic maintenance record and the insulation test report of the device for associated analysis to obtain the device state correlation degree, and the consistency degree of the measurement results and the actual state of the device is identified;

[0024] The current measurement results are compared and analyzed with the measurement data of the device during the historical normal operation to calculate the historical trend consistency, including the deviation degree and the trend consistency index;

[0025] The measurement accuracy score of each power collection terminal is allocated in combination with the multi-terminal consistency, the device state correlation degree and the historical trend consistency; and the measurement accuracy score data is used to determine the weight factor coefficient and the calibration priority of each power collection terminal in the calibration system.

[0026] Preferably, the specific process of adjusting the calibration parameters of the power collection terminal includes: recording the amplitude, frequency, phase characteristics of the partial discharge signal and the environmental temperature, humidity, air pressure and field strength data at the same time, and establishing a multi-dimensional time series database; separating the contribution of the environmental temperature and humidity from the partial discharge signal changes to extract the intrinsic state change signal of the device; performing time domain and frequency domain analysis on the separated intrinsic state change signal of the device to extract characteristic parameters reflecting insulation aging, including the discharge intensity growth rate, the spectral barycenter offset and the signal complexity change rate; performing pattern matching on the extracted characteristic parameters and the pre-established device aging feature database to judge the aging degree grade of the device; and selecting the corresponding gain compensation coefficient, noise filtering parameter and signal processing algorithm from the device aging feature database according to the aging degree grade, and setting the time interval of parameter update.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1. By setting the main calibration node, subarea calibration node and boundary calibration node in the grounding network of the open substation, combined with impedance matching and multi-path synchronous signal injection, multi-point distributed signal injection and detection are realized. The application considers the distance between the power collection terminal and the calibration node and the difference of the signal attenuation path by constructing a gradient calibration parameter distribution strategy, so as to reasonably distribute the calibration parameters according to the area. The relative consistency of the terminal measurement data is improved, the systematic error caused by environmental differences is reduced, and the accuracy of spatial positioning and tracking of partial discharge signals in the substation is enhanced.

[0029] 2. The application is based on a spatial positioning method combining time difference and intensity ratio analysis of the same partial discharge source detection data of multiple power collection terminals, combined with the physical attenuation law of electromagnetic wave propagation and the spatial coordinate database, the relative distance between the terminals is calculated through the signal intensity ratio matrix, and then the spatial back matching is carried out in the known device coordinate range, so as to lock the spatial position of the discharge source. At the same time, by comparing with the device spatial database, the spatial constraint boundary is established, which effectively limits the positioning search range, improves the positioning accuracy and calculation efficiency.

[0030] 3. The application realizes dynamic updating of the calibration parameters of the power collection terminal in the long-term operation process by introducing a dynamic parameter adjustment unit. The system not only collects the basic characteristic data of the partial discharge signal, but also synchronously records the external conditions such as environmental temperature, humidity, air pressure and field intensity, and establishes a time series multi-dimensional data model. On this basis, the system separates the interference of external environmental changes on the measurement signal through signal separation and feature extraction technology, extracts the index reflecting the intrinsic state change of the device, and compares with the device aging characteristic database to judge the aging degree of the device. According to the aging grade, the appropriate gain compensation, noise filtering and signal processing algorithm are matched to individualize the adjustment of the calibration parameters of the terminal. The problem of measurement error accumulation caused by device performance degradation or environmental change is effectively avoided, the limitation of traditional static calibration mode is broken through, and the long-term stable operation of the measurement system is realized. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A data calibration system structure schematic diagram based on a power collection terminal is provided for the application;

[0032] Figure 2 A data calibration flowchart schematic diagram based on a power collection terminal is provided for the application;

[0033] Figure 3 A discharge source spatial position acquisition flowchart schematic diagram is provided for the application;

[0034] Figure 4 A power collection terminal measurement accuracy acquisition flowchart schematic diagram is provided for the application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application.

[0036] Embodiment one:

[0037] The present application provides a kind of data calibration system based on electric power acquisition terminal, refer to Figure 1 System structure schematic diagram, technical scheme flow chart refer to Figure 2 , specific as follows:

[0038] Electric power acquisition terminal, for collecting partial discharge signal;

[0039] Calibration signal generation module is connected to the grounding network of open-type substation, for injecting the calibration signal of preset feature in the spatial distribution node of grounding network;

[0040] The spatial distribution node includes main calibration node arranged at the geometric center position of substation main grounding network, subarea calibration node arranged at different voltage level area grounding collection point respectively and boundary calibration node arranged at the boundary key position of grounding network, the distance between each node is determined according to the attenuation characteristic of calibration signal in grounding network, forms distributed calibration reference network and calibration redundancy mechanism;

[0041] The calibration signal generation module includes: multi-channel synchronous signal generator, for generating calibration signal with different identification characteristics to the main calibration node, subarea calibration node and boundary calibration node simultaneously;Impedance matching network is connected between each calibration node and grounding network respectively, for adjusting the injection parameter of calibration signal according to the grounding impedance characteristics of different injection points;Node state monitoring module is used to monitor the working state and signal injection of each calibration node in real time, and switch to backup calibration path when node failure is detected.

[0042] In the embodiment, by setting the main calibration node, the subarea calibration node and the boundary calibration node in the grounding network of the transformer substation, a distributed calibration reference network and a calibration redundancy mechanism are formed, a calibration signal with preset characteristics is injected by using a calibration signal generation module, and the accuracy of the partial discharge signal collected by the power collection terminal is improved. The multi-channel synchronous signal generator ensures the synchronicity and identifiability of the signals of each node, the impedance matching network optimizes the injection parameters according to the grounding impedance characteristics, and the calibration accuracy and consistency are improved. The node state monitoring module monitors the node state in real time and switches to the standby path when a fault occurs, and the system stability and reliability are enhanced. The system effectively improves the comprehensiveness of the calibration service, ensures the accuracy of the monitoring of the grounding network of the transformer substation, and thus improves the safe operation level of the power system.

[0043] Further, the determination method of the geometric center position of the main grounding network of the transformer substation comprises:

[0044] The CAD design drawings and actual construction records of the grounding network are collected to obtain the starting coordinates, the ending coordinates, the conductor length and the cross-sectional area data of each grounding conductor;

[0045] Based on the physical parameters of the grounding conductor, the product of the conductor length and the cross-sectional area is taken as a weight factor to calculate the geometric center coordinates of the grounding network;

[0046] The grounding impedance is measured at different positions to verify whether the calculated geometric center position is the electrical center, and when the deviation between the geometric center and the electrical center exceeds a preset threshold, the position of the main calibration node is adjusted according to the electrical center;

[0047] The main calibration node position data is used for subsequent power distribution of the calibration signal and optimization of the transmission path.

[0048] Further, the determination method of the boundary key position of the grounding network comprises:

[0049] Based on the grounding network topology map, the boundary nodes of the grounding network are identified, including the end nodes and branch connection points of the grounding conductor;

[0050] The current distribution simulation analysis method is used to calculate the distribution characteristics of the fault current in the grounding network, and the boundary area with high current density is determined;

[0051] Through the grounding impedance frequency response test, the boundary position with stable impedance characteristics in the calibration signal frequency range is identified;

[0052] The three factors of the boundary node position, the current distribution characteristics and the impedance stability are comprehensively considered, and a position with good signal transmission effect is selected as the boundary calibration node;

[0053] The boundary calibration node position data is used to form a complete distributed calibration coverage network.

[0054] Further, the acquisition method of the attenuation characteristics of the calibration signal in the grounding network comprises:

[0055] A low-frequency calibration signal of 1Hz to 100Hz is selected, and a test signal with a known amplitude and frequency is injected from different calibration nodes by a signal generator one by one;

[0056] The amplitudes and phases of the signals are synchronously measured by using a voltmeter and an ammeter at multiple measurement points of the grounding network, and signal attenuation data at different distances and different paths are recorded;

[0057] A relationship model between signal attenuation and transmission distance, frequency and conductor cross-sectional area is established according to the measurement data, and attenuation coefficients and phase delay coefficients are fitted;

[0058] The accuracy of the measured attenuation characteristics is verified by using an electromagnetic field simulation software, and the attenuation characteristic model is corrected and improved;

[0059] The attenuation characteristic data are used for optimizing the layout of calibration nodes and adjusting a calibration signal power distribution strategy.

[0060] By introducing geometric gravity calculation, electrical center verification, boundary node screening and signal attenuation modeling, scientific layout of main calibration nodes and boundary calibration nodes is realized, the accuracy and stability of calibration signal transmission are improved, and distributed calibration coverage effect and power distribution efficiency are optimized.

[0061] The data processing center comprises:

[0062] The calibration reference establishment unit is configured to control the calibration signal, receive detection data of the calibration signal from each power collection terminal, establish a distributed calibration reference by comparing measurement results of signals from different calibration nodes by different terminals, and establish a gradient calibration parameter distribution strategy according to distances of the power collection terminals from the calibration nodes and grounding impedance relationships;

[0063] The acquisition method of the distributed calibration reference comprises: recording signal amplitude, phase and harmonic distortion data of each power collection terminal during calibration signal injection, establishing a response characteristic data set; taking the power collection terminal with the most stable and highest measurement accuracy in the response characteristic data set as a reference terminal, calculating calibration coefficients of the power collection terminals relative to the reference terminal, including amplitude calibration coefficients and phase calibration coefficients; verifying the effectiveness of the calibration coefficients by injecting a verification signal with a known amplitude and phase, and establishing a confidence interval of the calibration coefficients.

[0064] In the embodiment, the distributed calibration reference and the gradient calibration parameter distribution strategy are established by the data processing center, so as to improve the calibration accuracy and consistency of the power acquisition terminal. The calibration reference establishment unit identifies and corrects the measurement difference between terminals by comparing the measurement results of different terminals on the same calibration signal; the calibration coefficient is calculated based on the terminal with the most stable and highest accuracy as the reference, and the effectiveness is confirmed by the verification signal, so as to ensure the accuracy and reliability of the calibration. The gradient calibration parameter distribution strategy considers the distance between the terminal and the calibration node and the relationship between the grounding impedance, realizes the individual calibration, and enhances the pertinence and effectiveness of the calibration. The system effectively improves the accuracy of partial discharge signal acquisition, and provides strong support for the reliable operation and fault prevention of the transformer substation.

[0065] Further, the specific process of verifying the effectiveness of the calibration coefficient includes:

[0066] A standard verification signal is injected from the calibration signal generation module;

[0067] Each power acquisition terminal applies the calculated calibration coefficient to calibrate the verification signal, and records the measurement result after calibration;

[0068] The absolute error and the relative error between the measurement result after calibration and the true value of the standard verification signal are calculated, and the mean, standard deviation and maximum of the error are calculated;

[0069] When the mean error is less than the preset allowable error threshold and the standard deviation meets the stability requirement, it is determined that the calibration coefficient is effective, otherwise the calibration coefficient is recalculated;

[0070] The effectiveness verification result is output in the format of error statistical report and eligibility determination result, including the error index of each terminal and the confidence level of the calibration coefficient;

[0071] The verification result is used to determine the update period of the calibration coefficient and the calibration quality grade evaluation.

[0072] By introducing the standard verification signal and the error statistical analysis mechanism, the accuracy and stability of the calibration coefficient of each power acquisition terminal are effectively verified, the calibration result is ensured to be true and reliable, and the calibration period and quality grade can be dynamically adjusted accordingly, so as to improve the long-term stability and data reliability of the whole system.

[0073] The acquisition method of the gradient calibration parameter distribution strategy includes: based on the measured data of the transformer substation grounding network, an electrical network including conductor material, cross-sectional area and connection relationship is established;

[0074] The simulation results of the low-frequency calibration signal in the electrical network are calculated, including transmission attenuation and phase delay characteristics; the weight factor of each power acquisition terminal affected by different calibration nodes is calculated based on the simulation results, and the weight factor distribution is obtained;

[0075] The power collection terminals are divided into a main calibration area, a secondary calibration area and a boundary calibration area according to the weight factor distribution, and different first calibration parameters and calibration frequencies are allocated.

[0076] In the embodiment, the weight factor of each power collection terminal affected by the calibration node is calculated by simulating the transmission attenuation and phase delay characteristics of the low-frequency calibration signal, and the power collection terminals are divided into a main calibration area, a secondary calibration area and a boundary calibration area according to the weight factor distribution, and calibration parameters and frequencies are allocated accordingly. The calibration accuracy and efficiency are improved, the resource utilization is optimized, the redundant operation is reduced, the accuracy of local discharge signal collection is enhanced, and the fault detection capability and the safety and reliability of the power system are improved.

[0077] Further, the specific content of the allocation of different first calibration parameters and calibration frequencies includes:

[0078] The power collection terminals in the main calibration area are allocated high-precision calibration parameters, including gain coefficient and phase compensation value, and daily calibration frequency is set;

[0079] The power collection terminals in the secondary calibration area are allocated standard-precision calibration parameters, including gain coefficient and phase compensation value, and weekly calibration frequency is set;

[0080] The power collection terminals in the boundary calibration area are allocated basic-precision calibration parameters, including gain coefficient and phase compensation value, and monthly calibration frequency is set;

[0081] According to the weight factor distribution of each area, the corresponding calibration algorithm priority and fault switching strategy are allocated for different areas;

[0082] The calibration parameter and frequency allocation data form a hierarchical calibration management strategy for optimizing the calibration efficiency and precision distribution of the entire system.

[0083] By setting calibration parameters and frequencies of different precision levels in different areas, a hierarchical calibration management strategy is constructed to realize differentiated management of each power collection terminal, thereby improving the overall calibration efficiency, avoiding resource waste, ensuring the operation of key areas, and enhancing the system stability and the ability to respond to faults.

[0084] The spatial positioning verification unit is configured to calculate the spatial position of the discharge source based on the detection data of at least two power collection terminals on the same local discharge source through the signal arrival time difference and signal attenuation characteristics, and match and verify with the pre-stored device spatial coordinate database to obtain the measurement accuracy of each power collection terminal.

[0085] The specific process of obtaining the spatial position of the discharge source is described in detail with reference to Figure 3, specifically: each power collection terminal records the signal peak amplitude and energy integral value of the same partial discharge event, and calculates the signal strength ratio matrix between each terminal; based on the physical principle that the signal strength is inversely proportional to the square of the distance when electromagnetic waves propagate in the air, the relative distance ratio of each power collection terminal to the discharge source is calculated using the signal strength ratio matrix; according to the pre-stored equipment spatial coordinate database, the equipment area where the partial discharge occurs is determined, and the spatial constraint boundary of the discharge source position is established; find the spatial position matching the relative distance ratio of each power collection terminal within the constraint boundary as the discharge source spatial position.

[0086] In this embodiment, the detection data of at least two power collection terminals is used to accurately calculate the spatial position of the partial discharge source in combination with the signal arrival time difference and attenuation characteristics, and is matched with the pre-stored equipment coordinate database, which significantly improves the positioning accuracy and reliability. Calculate the relative distance ratio to optimize fault detection efficiency and ensure the safe and stable operation of the power system.

[0087] The specific process of obtaining the measurement accuracy of each power collection terminal refers to Figure 4 , the specific process includes: collecting the measurement data of multiple power collection terminals monitoring the same equipment within the same time window to obtain multi-terminal consistency, including the standard deviation and coefficient of variation of the measurement results;

[0088] Correlate and analyze the measurement data of each power collection terminal with the periodic maintenance records and insulation test reports of the equipment to obtain the equipment state correlation degree, and identify the degree of consistency between the measurement results and the actual state of the equipment;

[0089] Compare and analyze the current measurement results with the measurement data during the historical normal operation of the equipment to calculate the historical trend consistency, including the deviation degree and trend consistency index;

[0090] Distribute measurement accuracy scores for each power collection terminal in combination with multi-terminal consistency, equipment state correlation degree and historical trend consistency; the measurement accuracy score data is used to determine the weight factor coefficient and calibration priority of each power collection terminal in the calibration system.

[0091] In this embodiment, the measurement accuracy of the power collection terminal is evaluated by comprehensively analyzing the multi-terminal consistency, equipment state correlation degree and historical trend consistency. The system combines real-time measurement data, equipment maintenance records and historical operation data to ensure that the measurement results are highly consistent with the actual state of the equipment, thereby optimizing the weight distribution and priority setting of the calibration system. The reliability and efficiency of the calibration system are improved, the priority calibration of the key terminal is realized, and the resource allocation is optimized.

[0092] The specific acquisition method of the measurement accuracy score includes:

[0093] A percentage system is established, in which the consistency of the multi-power collection terminal accounts for 40 points, the equipment state correlation accounts for 35 points, and the historical trend consistency accounts for 25 points;

[0094] The multi-terminal consistency of the power collection is scored, and a full score is given when the standard deviation is less than 5% of the measured value, and the deviation is deducted by the corresponding score for each increase of 1%;

[0095] The equipment state correlation is scored, and the degree of coincidence between the measurement results and the maintenance records is quantified, and a full score is given for complete coincidence, and the corresponding score is deducted for each inconsistency found;

[0096] The historical trend consistency is scored, the correlation coefficient of the current measurement trend and the historical normal trend is calculated, and a full score is given when the correlation coefficient is greater than 0.95, and the coefficient is deducted by the corresponding score for each decrease of 0.01;

[0097] The three scores are weighted and summed according to the weights to obtain the comprehensive measurement accuracy score of each power collection terminal, and the score results are divided into four levels of excellent, good, qualified and unqualified;

[0098] The measurement accuracy score data is used to determine the position of each terminal in the calibration transfer chain and the confidence level of the calibration parameters.

[0099] The dynamic parameter adjustment unit is used to monitor the long-term evolution trend of the partial discharge signal, identify the insulation aging state of the equipment, and dynamically adjust the calibration parameters of the corresponding power collection terminal according to the aging state.

[0100] The specific process of adjusting the calibration parameters of the power collection terminal includes: recording the amplitude, frequency, phase characteristics of the partial discharge signal, as well as the environmental temperature, humidity, air pressure and field strength data, and establishing a multi-dimensional time series database; separating the contribution of environmental temperature and humidity from the partial discharge signal changes, and extracting the intrinsic state change signal of the equipment; performing time and frequency domain analysis on the separated intrinsic state change signal of the equipment, extracting characteristic parameters reflecting insulation aging, including discharge intensity growth rate, spectral center shift amount and signal complexity change rate; matching the extracted characteristic parameters with the pre-established equipment aging characteristic database to determine the aging degree level of the equipment; selecting the corresponding gain compensation coefficient, noise filtering parameter and signal processing algorithm from the equipment aging characteristic database according to the aging degree level, and setting the time interval for parameter updating.

[0101] In this embodiment, the long-term trend of the partial discharge signal is monitored in real time, the insulation aging state of the equipment is identified, and the calibration parameters are dynamically adjusted according to the aging degree, thereby improving the accuracy and reliability of the monitoring system. Through multi-dimensional data analysis, the influence of environmental factors is separated, the intrinsic aging characteristics of the equipment are extracted, and the calibration accuracy is ensured. The automatic adjustment mechanism reduces manual intervention, improves operation efficiency, supports active maintenance, prolongs equipment life, and optimizes resource allocation. The technology realizes the intelligent linkage of calibration parameters and aging state, and promotes the development of the power system monitoring field.

[0102] The application discloses a data calibration system based on a power collection terminal, which forms a distributed calibration reference network and a calibration redundancy mechanism by setting a main calibration node, a partition calibration node and a boundary calibration node in a grounding network of a transformer substation, and injects calibration signals with preset characteristics by using a calibration signal generation module, thereby significantly improving the accuracy of the power collection terminal in collecting partial discharge signals. A multi-channel synchronous signal generator ensures the synchronicity and distinguishability of signals of each node, an impedance matching network optimizes injection parameters according to grounding impedance characteristics, and calibration accuracy and consistency are improved. A node state monitoring module monitors the state of the node in real time and switches to a backup path when a fault occurs, thereby enhancing the stability and reliability of the system. A data processing center further improves calibration accuracy and pertinence by establishing a distributed calibration reference and a gradient calibration parameter distribution strategy, thereby ensuring calibration accuracy and reliability. A spatial positioning verification unit uses multi-terminal data to obtain the position of a discharge source, thereby optimizing fault detection efficiency and ensuring safe and stable operation of the power system. The calibration efficiency is improved by optimizing the weight distribution and priority setting of the calibration system through comprehensive analysis of the consistency of multi-terminals, the correlation of equipment states and the consistency of historical trends. A dynamic parameter adjustment unit monitors the aging state of the equipment in real time, dynamically adjusts the calibration parameters, supports active maintenance and prolongs the service life of the equipment. The comprehensiveness of the calibration service is improved, the accuracy of the monitoring of the grounding network of the transformer substation is ensured, and strong support is provided for safe operation and fault prevention of the power system.

[0103] Embodiment two:

[0104] The application is applied to a specific open transformer substation as follows:

[0105] The transformer substation comprises a main transformer, a switch device, a lightning arrester, an insulator string and various electrical equipment, and the grounding network adopts a square grid arrangement. In order to realize comprehensive monitoring and accurate calibration of partial discharge in the transformer substation, the system is deployed according to the technical solution of the application.

[0106] According to the actual layout of the substation grounding network, three types of spatial distribution nodes are set in the substation grounding network. The main calibration node is set at the geometric center of the substation main grounding network, which is determined by collecting the grounding network CAD design drawings and actual construction records. The starting coordinates, ending coordinates, conductor length and cross-sectional area data of the main grounding conductor are obtained. Based on these physical parameters, the geometric center of gravity coordinates of the grounding network is calculated by taking the product of the conductor length and cross-sectional area as the weight factor. Subsequently, the grounding impedance measurement is carried out at this position and the surrounding area to verify the consistency of the geometric center and the electrical center, and the measured deviation meets the preset threshold requirement.

[0107] The partition calibration node is set at the grounding collection point of the 220kV, 110kV and 35kV three different voltage level areas. Through the analysis of the grounding network topology map, the boundary nodes are identified, including the end nodes and branch connection points of the grounding conductor. The current distribution simulation analysis method is used to calculate the distribution characteristics of the fault current in the grounding network, and the boundary area with high current density is determined. Through the grounding impedance frequency response test, the boundary position with stable impedance characteristics is identified within the calibration signal frequency range of 1Hz to 100Hz. By comprehensively considering the boundary node position, current distribution characteristics and impedance stability, the position with good signal transmission effect is finally selected as the boundary calibration node.

[0108] The frequency of the low-frequency sinusoidal wave is selected as the calibration signal, and the test signal with an amplitude of 5V is injected from the main calibration node, the partition calibration node and the boundary calibration node through the signal generator. The digital voltmeter and ammeter with accuracy level of 0.1 level are used to measure the amplitude and phase of the signal at the measurement points of the grounding network, and the signal attenuation data under different distances and different paths are recorded. According to these measurement data, the relationship model between signal attenuation and transmission distance, frequency and conductor cross-sectional area is established, and the simulation results are verified by ANSYS electromagnetic field simulation software, and the coincidence degree of the simulation results and the measured data is more than 95%.

[0109] The power collection terminal is distributed near the key equipment of the substation. During the calibration signal injection, each terminal records the signal amplitude, phase and harmonic distortion data, and establishes a response characteristic data set containing characteristic parameters. Through stability analysis, the terminal located beside the main transformer is selected as the reference terminal, and the measurement repeatability error of the terminal is less than 0.05%, and the long-term stability is better than 0.02%. Taking this as the reference, the calibration coefficients of other terminals are calculated, including the amplitude calibration coefficient and the phase calibration coefficient.

[0110] To verify the validity of the calibration coefficients, standard verification signals are injected from the calibration signal generation module. After the calibration processing using the calculated calibration coefficients, the absolute error between the calibrated measurement results and the true values of the standard signals is 0.08% on average, with a standard deviation of 0.03% and a maximum error of 0.15%. Since the average error is less than the preset 0.1% tolerance threshold, and the standard deviation meets the stability requirements, it is determined that all calibration coefficients are valid. The confidence interval of the established calibration coefficients is 95%, and the verification results are output in the error statistical report format, and the update period of the calibration coefficients is determined to be once a month.

[0111] Based on the measured data of the grounding network of the substation, an electrical network including the conductor material, cross-sectional area, and connection relationship is established. Through simulation calculation, the transmission attenuation and phase delay characteristics of the calibration signals in the grounding network at each frequency are obtained. According to the simulation results, the weight factors of the power collection terminals affected by different calibration nodes are calculated to form a weight factor distribution matrix.

[0112] According to the weight factor distribution, the power collection terminals are divided into three regions. High-precision calibration parameters are assigned to the terminals in the main calibration area, and daily automatic calibration is set. Standard-precision calibration parameters are assigned to the terminals in the secondary calibration area, and weekly automatic calibration is set. Basic-precision calibration parameters are assigned to the terminals in the boundary calibration area, and monthly automatic calibration is set.

[0113] When a partial discharge event occurs in the substation, the power collection terminals simultaneously record the discharge signals. By calculating the signal intensity ratio between each terminal, a ratio matrix is formed. Based on the physical principle that the signal intensity is inversely proportional to the square of the distance when electromagnetic waves propagate in air, the relative distance ratio of each terminal to the discharge source is calculated.

[0114] According to the pre-stored spatial coordinate database of the equipment, the coordinate range of the switchgear is determined, and a spatial constraint boundary of the discharge source position is established. Within the constraint boundary, an iterative optimization algorithm is used to find the spatial position that best matches the relative distance ratio of each terminal.

[0115] The accuracy of the power collection terminals monitoring the same main transformer is evaluated. The measurement data of the terminals within a 24-hour time window is collected, and the multi-terminal consistency index is calculated: the standard deviation of the measurement results is 3.2%. By correlating the measurement data of each terminal with the annual maintenance records and insulation test reports of the transformer, it is found that the degree of agreement between the measurement results and the actual state of the equipment reaches 92%. By comparing the current measurement results with the historical data of the equipment during the past two years of normal operation, the historical trend consistency correlation coefficient is calculated to be 0.96.

[0116] The system synchronously records the partial discharge signal characteristics and environmental data, and establishes a time series database containing temperature, humidity, air pressure, field strength and other dimensions. The data acquisition frequency is once per hour. Through multiple regression analysis, the contribution of environmental temperature to the total change is about 25%, the contribution of humidity is about 15%, and the remaining 60% is the change of the intrinsic state of the equipment.

[0117] The intrinsic signal after separation is analyzed in time and frequency domains, and characteristic parameters such as discharge intensity growth rate, spectral center shift, signal complexity change rate are extracted. These characteristic parameters are matched with the pre-established equipment aging characteristic database to determine that the transformer is in a mild aging state.

[0118] According to the mild aging level, the corresponding gain compensation coefficient, noise filter bandwidth and signal processing algorithm are selected from the parameter library, and the standard mode is switched to the enhanced mode. The parameter update time interval is set to every two weeks. The sensitivity of the transformer partial discharge detection is improved by 15% and the false detection rate is reduced by 20% after applying the adjusted parameters.

[0119] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A data calibration system based on a power collection terminal, characterized by, Comprise: Power acquisition terminal, for collecting partial discharge signal; Calibration signal generation module, connected to the grounding network of open-type substation, for injecting calibration signal with preset characteristics at the spatial distribution nodes of the grounding network; Data processing center, comprising: Calibration reference establishment unit, for controlling the calibration signal, and receiving the detection data of each power acquisition terminal to the calibration signal, establishing a distributed calibration reference by comparing the measurement results of different terminals to signals from different calibration nodes, and establishing a gradient calibration parameter distribution strategy according to the distance between the power acquisition terminal and each calibration node and the relationship of grounding impedance; Spatial positioning verification unit, for calculating the spatial position of the discharge source based on the detection data of at least two power acquisition terminals to the same partial discharge source through signal arrival time difference and signal attenuation characteristics, and matching and verifying with the pre-stored equipment spatial coordinate database to obtain the measurement accuracy of each power acquisition terminal; Dynamic parameter adjustment unit, for monitoring the long-term evolution trend of the partial discharge signal, identifying the insulation aging state of the equipment, and dynamically adjusting the calibration parameters of the corresponding power acquisition terminal according to the aging state.

2. The data calibration system based on power acquisition terminal according to claim 1, characterized in that: The spatial distribution nodes include a main calibration node arranged at the geometric center position of the main grounding network of the substation, partition calibration nodes arranged at the grounding collection points of different voltage level areas respectively, and boundary calibration nodes arranged at the key positions of the boundary of the grounding network, the distance between each node is determined according to the attenuation characteristics of the calibration signal in the grounding network, forming a distributed calibration reference network and a calibration redundancy mechanism; The calibration signal generation module comprises: a multi-channel synchronous signal generator for generating calibration signals with different identification characteristics to the main calibration node, partition calibration node and boundary calibration node at the same time; an impedance matching network connected between each calibration node and the grounding network respectively, for adjusting the injection parameters of the calibration signal according to the grounding impedance characteristics of different injection points; a node state monitoring module for monitoring the working state and signal injection of each calibration node in real time, and switching to a backup calibration path when a node fault is detected.

3. The data calibration system based on power collection terminal according to claim 1, characterized in that: The acquisition method of the distributed calibration reference comprises: recording the signal amplitude, phase and harmonic distortion data of each power acquisition terminal during the injection of the calibration signal, establishing a response characteristic data set; taking the power acquisition terminal with the most stable and highest measurement accuracy in the response characteristic data set as the reference terminal, calculating the calibration coefficients of the power acquisition terminal relative to the reference terminal, including amplitude calibration coefficient and phase calibration coefficient; verifying the validity of the calibration coefficients by injecting verification signals with known amplitude and phase, and establishing the confidence interval of the calibration coefficients.

4. The data calibration system based on power collection terminal according to claim 1, characterized in that: The acquisition method of the gradient calibration parameter distribution strategy comprises: based on the measured data of the grounding network of the substation, establishing an electrical network containing conductor material, cross-sectional area and connection relationship; Calculate the simulation results of low-frequency calibration signal in the electrical network, including transmission attenuation and phase delay characteristics; calculate the weight factor of each power acquisition terminal affected by different calibration nodes according to the simulation results, and obtain the weight factor distribution; The power collection terminals are divided into a main calibration area, a secondary calibration area and a boundary calibration area according to a weight factor distribution, and different first calibration parameters and calibration frequencies are allocated.

5. The data calibration system based on power collection terminal according to claim 1, characterized in that: The spatial position of the discharge source is specifically obtained by recording the signal peak amplitude and energy integral value of the same partial discharge event by each power collection terminal, and calculating the signal strength ratio matrix between the terminals; based on the physical principle that the signal strength is inversely proportional to the square of the distance when the electromagnetic wave propagates in the air, the relative distance ratio of each power collection terminal to the discharge source is calculated by using the signal strength ratio matrix; According to the pre-stored equipment spatial coordinate database, the equipment area where the partial discharge occurs is determined, and the spatial constraint boundary of the discharge source position is established; the spatial position matching the relative distance ratio of each power collection terminal is found as the spatial position of the discharge source within the constraint boundary.

6. The data calibration system based on power collection terminal according to claim 1, characterized in that: The specific process of obtaining the measurement accuracy of each power collection terminal includes collecting the measurement data of multiple power collection terminals monitoring the same equipment within the same time window, obtaining the multi-terminal consistency, including the standard deviation and coefficient of variation of the measurement results; The measurement data of each power collection terminal is associated and analyzed with the regular maintenance records and insulation test reports of the equipment to obtain the equipment state correlation degree, and the consistency degree of the measurement results with the actual state of the equipment is identified; The current measurement results are compared and analyzed with the measurement data of the equipment during the historical normal operation to calculate the historical trend consistency, including the deviation degree and trend consistency index; The measurement accuracy score of each power collection terminal is allocated in combination with the multi-terminal consistency, the equipment state correlation degree and the historical trend consistency; the measurement accuracy score data is used to determine the weight factor coefficient and the calibration priority of each power collection terminal in the calibration system.

7. The data calibration system based on power collection terminal according to claim 1, characterized in that: The specific process of adjusting the calibration parameters of the power collection terminal includes recording the amplitude, frequency, phase characteristics of the partial discharge signal, as well as the environmental temperature, humidity, air pressure and field strength data, establishing a multi-dimensional time series database; separating the contribution of environmental temperature and humidity from the partial discharge signal changes, extracting the intrinsic state change signal of the equipment; performing time domain and frequency domain analysis on the separated intrinsic state change signal of the equipment, extracting characteristic parameters reflecting insulation aging, including discharge intensity growth rate, spectral center shift amount and signal complexity change rate; the extracted characteristic parameters are matched with the pre-established equipment aging feature database to judge the aging degree grade of the equipment; according to the aging degree grade, the corresponding gain compensation coefficient, noise filtering parameter and signal processing algorithm are selected from the equipment aging feature database, and the time interval of parameter update is set.

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